Automatic focusing method

摘要

A method include scanning light from a light source which passes a confocal pattern on a sample through an objective lens while relatively moving one of the sample and the objective lens along a direction of an optical axis, acquiring two or more sectioning images by converting the light from the sample which penetrates the confocal pattern through the objective lens by a photoelectric converter, and changing an opening diameter of the variable diaphragm arranged at the pupil position of the objective lens or a conjugated position to the pupil position thereof to reduce a NA of the objective lens when focusing is not obtained and repeating an operation of taking two or more sectioning images by the photoelectric converter and obtaining the focusing position.